Communication Control Device, Communication Control Method, Program, and Communication Control System

1. A communication control device, comprising: power control circuitry configured to determine a transmission power of a wireless signal, which is transmitted from an interfering device, by using a fading index that is estimated based on a change in a relative distance between the interfering device and an interfered device, wherein the power control circuitry determines the transmission power by substituting the fading index into a calculation formula that expresses a water filling principle.

2. The communication control device according to claim 1 , wherein the calculation formula is derived by using a cutoff threshold value that is dependent on a deviation of fading.

3. The communication control device according to claim 1 , wherein the power control circuitry dynamically updates the transmission power by using an instantaneous value of the fading index.

4. The communication control device according to claim 3 , wherein the power control circuitry updates the calculation formula when the dynamically-updated transmission power causes interference exceeding an allowance in the interfered device.

5. The communication control device according to claim 4 , wherein the power control circuitry updates the calculation formula by using a quality indicator that is observed in the interfered device and by reference to a mapping table that maps the quality indicator and a parameter constituting the calculation formula.

6. The communication control device according to claim 1 , wherein the interfered device is a receiver station of a primary system, and wherein the interfering device is a transmitter station of a secondary system that secondarily uses a frequency channel that is protected for the sake of the primary system.

7. The communication control device according to claim 6 , wherein the communication control device is the transmitter station of the secondary system.

8. The communication control device according to claim 6 , wherein the communication control device is a server device that manages the secondary use of the frequency channel.

9. The communication control device according to claim 1 , wherein the power control circuitry estimates the fading index based on the change in the relative distance.

10. The communication control device according to claim 1 , further comprising: communication circuitry configured to receive the estimated fading index from a device that has estimated the fading index based on the change in the relative distance.

11. A communication control device, comprising: power control circuitry configured to determine a transmission power of a wireless signal, which is transmitted from an interfering device, by using a fading index that is estimated based on a change in a relative distance between the interfering device and an interfered device, wherein the fading index is estimated by substituting the change in the relative distance into an estimation formula that has coefficients that are precalculated based on a plurality of relative distances and a plurality of reception powers that are measured at the plurality of relative distances, respectively.

12. The communication control device according to claim 11 , wherein the calculation formula is derived by using a cutoff threshold value that is dependent on a deviation of fading.

13. The communication control device according to claim 11 , wherein the power control circuitry dynamically updates the transmission power by using an instantaneous value of the fading index.

14. The communication control device according to claim 13 , wherein the power control circuitry updates the calculation formula when the dynamically-updated transmission power causes interference exceeding an allowance in the interfered device.

15. The communication control device according to claim 14 , wherein the power control circuitry updates the calculation formula by using a quality indicator that is observed in the interfered device and by reference to a mapping table that maps the quality indicator and a parameter constituting the calculation formula.

16. The communication control device according to claim 11 , wherein the interfered device is a receiver station of a primary system, and wherein the interfering device is a transmitter station of a secondary system that secondarily uses a frequency channel that is protected for the sake of the primary system.

17. The communication control device according to claim 16 , wherein the communication control device is the transmitter station of the secondary system.

18. The communication control device according to claim 16 , wherein the communication control device is a server device that manages the secondary use of the frequency channel.

19. The communication control device according to claim 11 , wherein the power control circuitry estimates the fading index based on the change in the relative distance.

20. The communication control device according to claim 11 , further comprising: communication circuitry configured to receive the estimated fading index from a device that has estimated the fading index based on the change in the relative distance.

21. A communication control method, which is executed by a communication control device that controls a transmission power of an interfering device, the communication control method comprising: determining a transmission power of a wireless signal, which is transmitted from the interfering device, by using a fading index that is estimated based on a change in a relative distance between the interfering device and an interfered device, wherein the transmission power is determined by substituting the fading index into a calculation formula that expresses a water filling principle.

22. A non-transitory computer-readable medium encoded with instructions for causing a computer, which controls a communication control device, to function as: a power control unit configured to determine a transmission power of a wireless signal, which is transmitted from an interfering device, by using a fading index that is estimated based on a change in a relative distance between the interfering device and an interfered device, wherein the power control unit is further configured to determine the transmission power by substituting the fading index into a calculation formula that expresses a water filling principle.

23. A communication control system comprising: a wireless communication device of a second wireless communication system located in a cell of a first wireless communication system; and a communication control device configured to determine a transmission power of a wireless signal, which is transmitted from the wireless communication device, not to give harmful interference to the first wireless communication system, by using a fading index that is estimated based on a change in a relative position of the wireless communication device, wherein the communication control device is further configured to determine the transmission power by substituting the fading index into a calculation formula that expresses a water filling principle.

24. A communication control method, which is executed by a communication control device that controls a transmission power of an interfering device, the communication control method comprising: determining a transmission power of a wireless signal, which is transmitted from the interfering device, by using a fading index that is estimated based on a change in a relative distance between the interfering device and an interfered device, wherein the fading index is estimated by substituting the change in the relative distance into an estimation formula that has coefficients that are precalculated based on a plurality of relative distances and a plurality of reception powers that are measured at the plurality of relative distances, respectively.

25. A non-transitory computer-readable medium encoded with instructions for causing a computer, which controls a communication control device, to function as: a power control unit configured to determine a transmission power of a wireless signal, which is transmitted from an interfering device, by using a fading index that is estimated based on a change in a relative distance between the interfering device and an interfered device, wherein the fading index is estimated by substituting the change in the relative distance into an estimation formula that has coefficients that are precalculated based on a plurality of relative distances and a plurality of reception powers that are measured at the plurality of relative distances, respectively.

26. A communication control system comprising: a wireless communication device of a second wireless communication system located in a cell of a first wireless communication system; and a communication control device configured to determine a transmission power of a wireless signal, which is transmitted from the wireless communication device, not to give harmful interference to the first wireless communication system, by using a fading index that is estimated based on a change in a relative position of the wireless communication device, wherein the fading index is estimated by substituting the change in the relative distance into an estimation formula that has coefficients that are precalculated based on a plurality of relative distances and a plurality of reception powers that are measured at the plurality of relative distances, respectively.